Continuous rotation rock drill

ABSTRACT

A rock drill having a drill rotation motor coaxial with the percussion motor hammer piston and surrounding the striking bar of the drill.

Bauifley et a1. 1 1 Jan. 7, 1975 [54] CONTIINIUOUS ROTATION ROCK DRILL1,846,817 2 1932 Smith, Jr 173 105 x 1 1 Edward Bafley, 2, 5131????15/1323 5213119711333: 13311:..131123 BOX 37, Newport, -H- 0377?;3,059,618 10/1962 Osgood 173/105 x Walter Fish, 14 Hlghlandvlew3,116,666 1/1964 36611 418/196 x Rd, Claremont, NH. 03743; Rene3,191,693 6/1965 Lincoln 173/105 X Pertusio, PO. Box 757, Goshen,3,528,345 9/1970 Rumsey 1 418/196 X 03752 3,666,024 5/1972 Beaumont.173/105 3,685,593 8/1972 Amtsberg 173/105 X [22] F11ed: Sept. 28, 1972FOREIGN PATENTS OR APPLICATIONS [21] Appl' 293393 568,813 4/1945 GreatBritain 173/59 [52] US. Cl 173/59, 173/78, 173/105, P i Examiner- ErnestR Purser 7 173/DIG- 2, 418/1 Assistant ExaminerWi11iam F. Pate, 111 [51]Int. Cl B25d 9/00 Atto ney, Agent, or FirmH0ward E, Sandler [58] Fieldof Search 173/105, 106, 107, 108,

173/59; 418/196, 227 [57] ABSTRAQT [56] References Cited A rock drillhaving a drill rotation motor coaxial with UNITED STATES PATENTS the[JEFCiJSSlOH motor hanimer piston and surrounding 1 the strikmg bar ofthe dull. 1,459,402 6/1923 Johnson 173/108 1,605,712 11/1926 Gilman173/105 9 Claims, 4 Drawing Figures PATENTED JAN 7 I975 SHEEY 10F 2 1CUNTINIUOUS ROTATION ROCK DRILL In the field of rock drill engineeringit is well known to provide a rock drill apparatus having a percussionmotor with a reciprocating hammer piston and an independently operabledrill rotation motor for rotating the striking bar of the rock drill andthereby providing rotation of the drill steel and bit.

In the rock drill apparatus of the prior art the drill rotation motorhas been mounted generally alongside the percussion motor in a portionof the housing extending laterally from the outer surface of thepercussion motor cylinder. The present invention provides anindependently operable rotation motor having the main drive member andgear reduction elements coaxial with or symmetrically distributed aroundthe striking bar of the rock drill so that the rock drill housing isfree of any lateral extension for the rotation motor. This design yieldsobvious advantages over prior designs in a better balanced apparatus,reduced space requirements for the housing, better muffler arrangement,multiple tooth engagement of the drive gearing and better lubrication ofthe striking bar and associated rotating parts.

These and other advantages and objects of the present invention will bemore readily appreciated upon consideration of the following descriptionand drawings in which:

FIG. 1 is a median sectional view of a rock drill constructed accordingto the principles of this invention taken substantially on line ll-1 ofFIG. 2 looking in the direction indicated by the arrows;

FIG. 2 is a three dimensional view of the rock drill of FIG. 1 on asmaller scale, with portions broken away to show details of the rotationmotor and planetary drive;

FIG. 3 is a sectional view taken substantially on line 33 of FIG. 2looking in the direction indicated by the arrows;

FIG. 4 is a fragmentary sectional view taken substantially on line 4-4of FIG. 1 looking in the direction indicated by the arrows.

In FIG. 1 there is shown a sectional view of a percussive rock drillgenerally indicated at of the valveless type described and shown in US.Pat. No. 3,666,024 and provided with a hammer piston 12 having a stemportion 14 with passageways therein for controlling the compressed airwhich produces reciprocation of the hammer piston 12 within a cylinderbody 16 having a back head 17 as more fully described and illustrated inthe above cited US. patent.

Coaxial with the hammer piston 12 is an elongated generally cylindricalstriking bar 20 extending inwardly from beyond the forward end of therock drill 10 (to the right as seen in FIGS. 1 and 2) throughapproximately half the length of the drill It) to a point within thedrill where it may be struck by the hammer piston 12 upon reciprocationthereof. The striking bar 20 has external splines 21 in a centralportion to provide a slidable driving engagement with internal splines23 of a chuck 22 having small external splines 24 on the forward endportion thereof for a purpose to be disclosed.

An elongated, hollow, generally cylindrical planetary carrier member 28internally drivingly receives the chuck 22 along with a chuck bushing 26rearwardly abutting the chuck 22 to slidably support the rearward end ofthe striking bar 20. Forward and rearward end portions of the carriermember 28 are rotatably supported against both radial and axial forcesby suitable bearings as for instance the tapered roller bearings shownas elements 30 and 31, front and rear bearings respectively. Thebearings 31 and 30 are respectively mounted in a yoke portion 34 and aplanetary gear cover portion 36, respectively, of the body of the rockdrill l0, rigidly secured together and to the rock drill body byelongated threaded members such as side rods 38 (see FIG. 3) and siderod nuts 39 abutting a front cover portion 40 of the rock drill body toremovably secure the portions 34, 36 and 40 in coaxial abuttingrelationship as well as the cylinder body 16 with the back head 17.

A wide flanged air motor bearing support 42 having a hub portionradially spaced from and surrounding an intermediate portion of thecarrier member 28 is assembled with an air motor gear housing 44 and anair motor front plate 46 to form the body of the rotation motor 47 ofthe instant invention. Mounted on the hub portion of the air motorbearing support 42 is a pair of needle type roller bearing assemblies 48to rotatably support an air motor drive gear 50 hereinafter morecompletely described but having (as been seen in FIG. 1) a forwardlyextending externally toothed portion 52 which is the driving sun gearfor a set of planetary speed reduction gearing incorporating the beforementioned carrier member 28 on which are rotatably mounted a pluralityof pinions 54 (see FIG. 2) in toothed engagement with the gear portion52 and the internal teeth of a fixed planetary gear 56 rigidly securedbetween the yoke 34 and planetary gear cover 36 and rigidly securedagainst rotation by the side rods 38 extending through notches 57 in theexterior periphery of the fixed gear 56.

In FIG. 3 the air motor drive gear is seen to have on its periphery aplurality of teeth of two different sizes namely large teeth 60 andsmall teeth 62. The large teeth 60 (8 are shown) are spaced apartapproximately three times the normal pitch for that size of tooth andthe small teeth 62 are formed in between the large teeth 60 (six smallteeth 62 are shown between each pair of large teeth 60). The drive gear50 and the large teeth 60 thereon are suitably sized to rotate with verysmall clearance within the central bore 45 of the gear housing 44 tominimize leakage of air between the large teeth 60 and the bore 45 whenthe rotation motor 47 is operating.

Meshed with the drive gear 50 is a pair of air motor idler gears orpinions 64 provided with toothed spaces complementary to the large andsmall teeth 60 and 62 of drive gear 50 so that the idler gear 64 show apair of large tooth spaces 65 with small tooth spaces 66 therebetween ofa number equal to the number of small teeth between each two large teethon the drive gear 50. The purpose of the large teeth on the drive gear50 is to provide air capacity for a powerful rotation motor while thesmall teeth on the gears 50 and 64 make for smooth operation of thepinion 64 not possible with gear teeth the size of the large teeth 60.

As best seen in FIG. 2 the gears 50 and 65 have a face width muchgreater than normal for this size gearing for the purpose of providingmore air capacity to increase the power of the rotation motor.

It is to be noted that the above described construction of the air motorand the planetary reduction gear set provides that the carrier member 28if mechanically isolated from the rotation motor 47 so that damage to orfailure of one of these will not cause trouble in the other member.

As best seen in FIG. 2 three fluid conducting elements, illustrated ashoses 70, 71 and 72, respectively communicate with an air manifold 74rigidly secured to the side of the yoke 34 of rock drill to providecompressed air to the rock drill 10. As will be seen the central hose 71is larger than the other two hoses and is used for the supply of air tothe percussion motor to reciprocate the piston 12 backward and forwardin the cylinder body 16 in a well known manner as set forth in the abovecited US. patent. The supply of air through the hose 71 is controlled byusual valve means (not shown) communicating with a source of compressedair such as a compressor. Other control means (also not shown) are usedto selectively connect hose 70 or 72 to the source of compressed air andsimultaneously to connect the other of the two hoses 70 and 72 to theoutside atmosphere for exhausting of a portion of the compressed airfurnished to the rotation motor as hereinafter made plain.

The manifold 74 is provided with passageways (not shown) communicatingthe hoses 70 and 72 with respective passageways in the front yoke 34which in turn communicate with respective bores 76 and 77 through thebearing support 42 which in turn communicate with open sided boreportions 76 and 77 in the gear housing 44 which communicate with thespaces between the drive gear 50 and the bore 45 of the housing 44adjacent opposite sides of the pinion 64 (see FIG. 3).

Referring again to FIG. 4 it is to be seen that bores 76 and 77 arecross connected by suitable air conducting grooves 80 and 81 in the faceof bearing support 42 with similar bores 78 and 79 respectively throughthe flange portion of bearing support 42 which in turn communicate withpartial bores 78' and 79, respectively, on opposite sides of a secondpinion 64' communicating with the space between drive gear 50 and thebore 45 on opposite sides of the second pinion 64' so that when pressurefluid or compressed air is furnished to hose 70 (see FIG. 2) suchcompressed air will be provided to the bores 76 and 78 and the partialbores 76 and 78' and the spaces between the drive gear 50 and the bore45 on the left hand side of gear 64 as seen in FIG. 3 and on the righthand side of gear 64' as seen in that figure. Thus, with pressurefurnished as above stated the drive gear 50 will be rotated in thedirection shown by arrow 68 in the middle of FIG. 3.

When the hose 70 is connected to compressed air the hose 72 will beconnected to the atmosphere which in turn connects the bores 77 and 79;and the partial bores 77' and 79 and the spaces between drive gear 50and the bore 45 on the right hand side of gear 64 and on the left handside of gear 64'; to the atmosphere for the purpose of exhausting airwhich travels around the exterior of the pinion 64 and 64' duringrotation under the force of the compressed air.

Two other partial bores 84' and 85 left and right hand in FIG. 3 andright and left hand bores 84 and 85, respectively in FIG. 4 communicatefrom the spaces between the drive gear 50 and the bore 45, through theflange of the bearing support 42, with exhaust passages 88 and 89 in thefront yoke 34 which in turn are pennanently connected to internal volume90 ofa muffler 91 surrounding the cylinder body 16 of the rock drill l0.Whenever air is furnished to either bores 76 and 78 or bores 77 and 79the compressed air after pushing the large gear teeth 60 on the drivegear 50 past the exhaust port 84' or 85' air will be exhausted directlyfrom the space between the drive gear 50 and the bore 45 to the mufflervolume 90 wherein the sound of the exhaust will be greatly attenuatedbefore coming into contact with the ambient atmosphere to provide soundlevel reduction in a well known manner.

It should be readily apparent that provision of compressed air to hose72 will provide compressed air to bores 77 and 79 and partial bores 77and 79 with resultant force reversal to provide for reverse rotation ofthe drive gear 50. When the hose 72 is connected to the pressure sidethe hose will be connected to atmosphere and exhaust by way of partialbores 78 and 76 through the bores 78 and 76 and the hose 70 will besimilar to the exhaust through 72 during forward rotation. The mainexhaust will still be through the bore portions 84' and and the bores 84and 85 to passageways 88 and 89 through muffler volume during reverserotation.

Referring again to FIG. 1 it will be seen that a passageway 92 extendsobliquely forwardly and inwardly from passageways 88 and 89,respectively, to the roller portion of bearing 31. The passageways 92provide for the use of some exhaust air bled off from the passageways 88and 89 to travel through the bearing 31 and the spaces around andbetween the striking bar 20 and the chuck driver 22 and chuck bushing 26and forwardly through the bearing 30 to provide cooling and lubrication(from a well known air line oiler) to the bearings and other rotatingand sliding parts in a very desirable manner.

As regards the operation of the rock drill 10 of this invention theabove described rotation of the air motor drive gear 50 is of coursetransferred to the sun gear 52 and the pinions 54. The pinions 54 beingin engagement with the stationary gear 56 will travel around the innerteeth of the gear 56 and carry with them the carrier member 28 which isin turn drivingly engaged by means of splines 24 with chuck 22, thesplines 23 of which slidingly engage the splines 21 of the striking bar20 to provide the desired rotation thereof.

Such rotation is of course transferred through coupling means (notshown) to drill steels and drill 'bits connected to the rock drill 10 ina well known manner to provide for the rotation of the drill duringdrilling and also to provide rotation for threadingly engaging anddisengaging the couplings and drill steels as desired.

Although a particular embodiment of the rock drill of this invention hasbeen hereinabove described, it is to be realized that other embodimentsof the principles of this invention are envisioned and possible. It istherefore respectfully requested that this invention be interpreted asbroadly as possible within the scope of those principles.

What is claimed is:

l. A pressure fluid actuated rock drill comprising: an elongatedcylinder body; a piston member reciprocable in said cylinder body alongthe central longitudinal axis of said body; passageway means adapted tobe con-' nected to a fluid pressure source to supply fluid underpressure to reciprocate said piston member in said body; an elongatedstriking bar slidably rotatably mounted in said body and coaxialtherewith to receive blows from said piston; a fluid operated reversibledrill rotation motor symmetrical about said axis and in drivingcommunication with a striking bar chuck driver for the selectiverotation of said striking bar in opposite directions about thelongitudinal axis thereof; and speed reduction gear means including aset of planetary gears coaxial with said rotation motor and in drivingengagement between said rotation motor and said chuck driver.

2. A rock drill as specified in claim 1 wherein said passageway meansinclude cooperable passageways in said hammer piston and in saidcylinder body.

3. The rock drill as specified in claim 2 wherein said piston membercomprises a head portion and an elongated stem portion and saidpassageways in said piston member are in said stem portion.

4. The rock drill as specified in claim 1 wherein said rotation motorcomprises; a double pitch driving gear coaxial with said body, aplurality of double pitch driving pinions equidistant from said axis,and fluid conducting passageway means for rotation of said striking barin either a forward or a reverse direction.

5. The rock drill as specified in claim 4 wherein said speed reductiongear means is supported on antifriction bearing means at each end ofsaid motor and said driving gear is supported independently of saidspeed reduction gear means.

6. The rock drill as specified in claim 5 wherein said support of saiddriving gear includes antifriction bearing means.

7. The rock drill as specified in claim 1 additionally comprising amuffler and said rotation motor has primary exhaust connectionspermanently connected to the interior of said muffler.

8. The rock drill as specified in claim 7 wherein said rotation motorhas anti-friction bearings at both axial ends thereof with secondaryexhaust passageway means conducting exhaust fluid from said rotationmotor to said bearings.

9. The rock drill as specified in claim 8 wherein said secondary exhaustpassageway means also communicate with the exterior of said strikingbar.

1. A pressure fluid actuated rock drill comprising: an elongatedcylinder body; a piston member reciprocable in said cylinder body alongthe central longitudinal axis of said body; passageway means adapted tobe connected to a fluid pressure source to supply fluid under pressureto reciprocate said piston member in said body; an elongated strikingbar slidably rotatably mounted in said body and coaxial therewith toreceive blows from said piston; a fluid operated reversible drillrotation motor symmetrical about said axis and in driving communicationwith a striking bar chuck driver for the selective rotation of saidstriking bar in opposite directions about the longitudinal axis thereof;and speed reduction gear means including a set of planetary gearscoaxial with said rotation motor and in driving engagement between saidrotation motor and said chuck driver.
 2. A rock drill as specified inclaim 1 wherein said passageway means include cooperable passageways insaid hammer piston and in said cylinder body.
 3. The rock drill asspecified in claim 2 wherein said piston member comprises a head portionand an elongated stem portion and said passageways in said piston memberare in said stem portion.
 4. The rock drill as specified in claim 1wherein said rotation motor comprises; a double pitch driving gearcoaxial with said body, a plurality of double pitch driving pinionsequidistant from said axis, and fluid conducting passageway means forrotation of said striking bar in either a forward or a reversedirection.
 5. The rock drill as specified in claim 4 wherein said speedreduction gear means is supported on antifriction bearing means at eachend of said motor and said driving gear is supported independently ofsaid speed reduction gear means.
 6. The rock drill as specified in claim5 wherein said support of said driving gear includes antifrictionbearing means.
 7. The rock drill as specified in claim 1 additionallycomprising a muffler and said rotation motor has primary exhaustconnections permanently connected to the interior of said muffler. 8.The rock drill as specified in claim 7 wherein said rotation motor hasanti-friction bearings at both axial ends thereof with secondary exhaustpassageway means conducting exhaust fluid from said rotation motor tosaid bearings.
 9. The rock drill as specified in claim 8 wherein saidsecondary exhaust passageway means also communicate with the exterior ofsaid striking bar.